Allow String-to-byte[] coercion for String-value collections

[cowtowncoder]

(note: follow-up for FasterXML/jackson-dataformats-binary#188)

So: currently binary values (supported by some binary formats, but not textual formats like JSON or XML) can be coerced into String values (see StringDeserializer.deserialize() special case for JsonToken.VALUE_EMBEDDED_OBJECT); same is true for Tree Model based handling.
This is implemented by re-encoding binary as Base64 content.
However, specialized String-value collection/array deserializers are missing this case: they use method "_parseString()" from StdDeserializer.

Given that default String handling does this, it makes sense to support same coercion for container cases.

Note: testing probably needs to be done from format modules as JSON backend can not induce VALUE_EMBEDDED_OBJECT tokens (although testing handling of TokenBuffer might make sense -- maybe easiest still via binary codecs): for example, from cbor backend for which original issue was reported.

[cowtowncoder]

Will be fixed in 2.10.1